Field of the Invention
The invention relates to a computer-implemented method for calculation and output of control pulses by a control unit, wherein the control unit has a first computing unit and a second computing unit, and wherein the control pulses are output by the control unit to an internal combustion engine. Moreover, the invention also relates to a control unit in this connection for calculation and output of control pulses to an internal combustion engine, wherein the control unit has a first computing unit and a second computing unit.
Description of the Background Art
Methods for calculation and output of control pulses by a control unit have been known ever since control units, in the form of engine control units for example, have been implemented on the basis of electronic computing units. These computing units are fundamentally programmable, whether through the programming of a processor-based computing unit or through the programming of a programmable logic element, for example in the form of an FPGA, or through the “programming” of a hardware unit through a hardware description.
The control pulses calculated and output to an internal combustion engine by the control unit can be of a wide variety of types. Typically, these are pulses for controlling the fuel injection (in gasoline and diesel engines, for example) and pulses for controlling the fuel ignition (for example in gasoline engines). However, the control units can also issue other control pulses, for example for controlling the throttle valve or for emissions control (lambda control).
In order to calculate the control pulses, the control unit normally processes a variety of sensor data, for example information about the position of the crankshaft and camshaft, the air mass flow, the air mass temperature, the position of the throttle valve, and other sensor data.
Internal combustion engines are highly dynamic systems in operation, with rapid state changes, and require very fast closed-loop control systems. These closed-loop control systems are implemented on and with the computing units of the control unit, where the computing units are—in any case additionally—real-time control systems. The hardware implementation of control units always requires resolving the conflict between the most powerful, fastest hardware and the need for strict control of costs; by its nature, this is a tradeoff.
It is possible that the sampling rates achievable with the computing units of the control unit will not permit open-loop and/or closed-loop control algorithms to be executed sufficiently rapidly that each control pulse can be calculated anew with sensor data and/or state data updated in each sampling step. In this case a plurality of control pulses is calculated based on prior state data and is successively output by the control unit to the internal combustion engine, implementing a type of feed-forward control. In contrast, if it is essential to always be able to achieve sufficiently high sampling rates to calculate every single control pulse anew using current state data, extremely high cost increases must be accepted in the implementation of the control units due to the use of very powerful hardware components.